Rev range for a 2.8 TD MU ?

[elysian]

I'm fairly new to diesel engines, more familiar with motorbike engines, so going from 12k rpm to 3k rpm is a bit of a change

anyway, the MU i have, will rev thru to 3k no problem, but over 3k, it doesn't rise quickly or seem to want to rev past 3250 ish .. almost like I'm hitting a rev limiter ....during my daily driving and that, I usually shift up a gear around the 2700-3k mark , so it's not really a big issue, but I was wondering if this is "normal" for the engine/MU/etc itself ?

also, I know it's a turbo diesel, but there doesn't seem like there is a "surge" in the rev's like in a car when the turbo spools up .. or a "struggle" in the rev's if it falls below a certain rpm .. the MU just seems to power on regardless of the rpm.. from idle (750-ish) to 3k, no surge, or struggle ..

anyway .. these are just my diesel "newbie" questions / ramblings , so any insight would be greatly appreciated..

[geeves]

You might have a turbo problem or a restriction in the inlet or exhaust. The 2.8 likes to rev (by diesel standards) It should be sluggish below 1500 build in power from 1500 to about 2200 then all hell should break loose all the way to nearly 4000. Rev limiter is at 4200 and you know when you hit it. Peak torque is at about 2500 and peak hp at 3800

[turnturn]

With my 2.8 there is not much happening until about 1800rpm where there is a noticable increase in power up to about 3500rpm where it goes flat. It will rev further but struggles.
Engine has done 270,000 ks and is unmodified except for a slightly improved exhaust.

[mudgrip4]

To add extra top end pull and 15hp overall, get diesel mechanic to advance diesel pump timing. Works a treat and added an extra useable 500rpm to my last 2.8

Mike

[geeves]

couple of questions to ask before doing anything.What ecconomy are you getting open road. If your not getting 32mpg at 100kph on fairly flat roads or 30 at 120 you have an issue to fix.
Basic maintenance items to do before anything else are the air and fuel filter These should help heaps. Then make sure the turbo is working right but this will need to borrow a boost guage You should be seeing at least 10psi but anything up to 15 is good although you are unlikly to get the higher number on a standard induction and exhaust. Exhausts make a big difference but are expensive so leave till last unless your current exhaust is on the way out. Snorkels are good They also protect the engine from dust and water if you can find any. They feed cooler air to the engine as well. There are tweaks to the diesel pump and injectors that do help but its best to talk to an expert for these and have your credit card handy.

[Jimmu]

Sounds to me like my sisters 3.1L MU.

It reved hard to 3k and pulled like a freight train but then died.

The turbo was dying and by the look of it was rubbing on the housing once it got that high and was slowing down the exhaust flow.

On Stock boost the turbo surge is not that evident. Wind up the boost and fuel and it is like a freight train to 4500

As for the fuel consumption. 28mpg is common on mine. 24-26 towing a trailer. The tires and what you carry around with you have a big effect.

Jimmy

Jimmy

[elysian]

hhmm, got me thinking now..

over the week end, I went down the coast and did about 650 km, used about 60 litres of juice.. so about 6.5km/l , which is like about 15mpg (US)/18mpg(UK) .. so I should be getting about double the k's I'm getting now .. hhmm..

I've only had the MU for about 8 months now and had no real issues with it.. only had to replace the alternator (diode pack fried itself), new tyres (old tyres had like 5-6mm of tread left) and every 5000km's I change the oil/oil filter..

I had a llok at the air filter after I read the replies.. looks clean, but I might look into getting a new one anyway, might see if I can get a K&N one .. I think I saw a thread about which one is the right one for the MU ..

As for a snorkel, I might put one on eventually, but since it's also my daily driver, the closest it would get to off-road is driving across some grass or a muddy construction site at work..

Other than that, I'll save a bit of $$$ , take a few days off work and put the MU into a diesel mechanic and see what they say ..

I'm beginning to suspect that I may of bought a can of worms with this perticular MU ..

[geeves]

Time to redo your maths class. Thats about 6.5l/100km or 11km/l which is actualy quite good.Its also over 900km on a tankfull of diesel. Even my corrola isnt getting that good.
Change the fuel filter before anything else If your air filter looks clean then its probably ok

[elysian]

to follow up to this..

I did a run down the south coast again on the weekend, down to Berry for a family lunch outing ..

On the way down I decided to see if it was just my driving style that threw me on the rev range..

My MU will rev to 4200 quite easily actually in 1st,2nd &3rd, just gets a bit noisy after about 3300-ish .. in 4th after about 3500-ish it seems to slow down a bit and take awhile to wind up to 4000, and 5th, I didn't get it over 3500, as I was doing about 160km/h ;D

Anyway.. when I get the car serviced next , I'll get the mechanic to change the fuel filter when he does the oil/filter ..

It's probably just a querk with my dash, but the fuel guage goes from full to the empty line after doing about 600-650 km's .. the little fuel light doesn't come on .. so I might see how far it will go before the light shows up.. giving the calculations Alan posted before, I should be getting about another 200-250 odd k's before I need to fill up again .. (( BTW, what is the size/capacity of a '93 2.8TD MU's fuel tank ? 80 litres? )

[geeves]

tank is 83 liters. The gauge is a wire wound type and may be faulty. Mine would drop to empty at 250km. A new sender fixed